Your entry is controlled by a breaking point in your geometry (Sometimes you will need to break the geometry a surd-en place, to get your desired entry point).
After you have chained your geometry (before pressing done) you will see a option saying "change strt". This feature will give you the option to move your chain arrow.
In your "Roughing/Finish parameter" you will find the option to check "Entry-ramp" and the button will light up. In here you will find all kind of parameters, try to play around with them, also use the help option Mastercam have done a good job explaining the different features. also try Ebay for version 9 tutorial books, they are worth every dime.